A40-47 Neuromyelitis Optica Spectrum Disorder Presenting With Bilateral Optic Neuritis and Concomitant Interstitial Lung Findings: A Multisystem Diagnostic Challenge

Learning Objectives 1. Recognize that neuromyelitis optica spectrum disorder (NMOSD) can rarely present with pulmonary manifestations mimicking interstitial lung disease. 2. Discuss the diagnostic and therapeutic considerations in patients with simultaneous optic neuritis and unexplained pulmonary infiltrates. 3. Highlight the importance of multidisciplinary coordination between pulmonary and neuro-immunology services in complex autoimmune cases. Introduction Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune demyelinating disease of the central nervous system characterized by recurrent optic neuritis and transverse myelitis mediated by aquaporin-4 (AQP4) antibodies. Although primarily neuro-astrocytic, NMOSD may coexist with systemic immune or pulmonary findings, potentially confounding diagnosis. We report a case of anti-AQP4-positive NMOSD presenting with acute bilateral optic neuritis and concurrent interstitial lung abnormalities, emphasizing the expanding clinical spectrum of this disease.A 47-year-old woman with anxiety and depression presented with acute bilateral vision loss over four days, following a 40-lb unintentional weight loss over three months. MRI orbits demonstrated bilateral optic nerve hyperintensity and enhancement; MRI brain showed nonspecific white matter changes, and MRI cervical spine was unremarkable. CSF analysis excluded infectious, paraneoplastic, or demyelinating etiologies. Serum NMO-IgG titer >1:100,000 confirmed NMOSD.She received IV methylprednisolone 500 mg BID × 5 days, followed by plasma exchange × 5 sessions with partial visual recovery. Neuro-immunology recommended inebilizumab for long-term therapy.CT Chest revealed bilateral reticular infiltrates and small nodules. Bronchoscopy was negative for malignancy or fungi. Transbronchial biopsies from the main carina and lower lobes did not show any diagnostic abnormalities. Discussion This case illustrates NMOSD as a multisystem autoimmune disease that can overlap with pulmonary pathology. Although lung involvement is rare, organizing pneumonia and interstitial patterns have been reported in AQP4-positive NMOSD, possibly due to AQP4 expression in alveolar epithelium. The coexistence of visual loss, weight loss, and interstitial changes led to a broad differential, including paraneoplastic and infectious processes. Recognition of this overlap is essential, as early immunotherapy and PLEX can prevent irreversible neurologic and pulmonary sequelae.This case reinforces the need for interdisciplinary collaboration between pulmonary and neurology services when evaluating atypical inflammatory or autoimmune presentations. References 1. Ra JS et al. Cryptogenic Organizing Pneumonia Associated with Late-Onset NMOSD. SAGE Open Med Case Rep.2022;10:2050313X2210957. 2. Lai C et al. Transient Organizing Pneumonia at Onset of NMOSD. eNeurologicalSci. 2023;31:100442. 3. Takeuchi M et al. Organizing Pneumonia as Initial Presentation of AQP4+ NMOSD: A Case and Literature Review. Cureus. 2025;17(1):e74625. This abstract is funded by: None